| 摘要: |
| 为了探究黄土高原南部旱地土壤肥力降低的原因,在长期水土流失监测的基础上,采用土壤颗粒分级的方法,对黄土高原南部旱地土壤不同颗粒级有机碳、氮的分布规律及其与土壤侵蚀的关系进行了研究。结果表明,侵蚀性旱地土壤粘粒中的有机碳、氮含量最高,粉粒次之,沙粒最低,有机碳、氮主要分布在〈50 μm的粘粒和粉粒中,分别占土壤总量的97.07%和85.25%;随农地土壤产沙量的增加,各颗粒级中的有机碳、氮含量呈减小趋势,土壤粘粒中的有机C/N逐渐增加,砂粒中的有机C/N逐渐减小;产沙量与土壤粘粒、粉粒和砂粒中的有机碳、氮含量间存在着显著和极显著的线性相关性。因此可以认为,黄土高原细小土壤颗粒的大量流失,是导致该区土壤肥力水平降低的根本原因。 |
| 关键词: 黄土高原 土壤侵蚀 旱地土壤 土壤颗粒级 有机碳、氮分布 |
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| 基金项目:教育部留学回国人员科研启动基金项目；西北农林科技大学校长基金项目（08080202） |
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| Effect of soil erosion on distribution of C and N in different particle size fractions of soil on the southern Loess Plateau |
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| Abstract: |
| On the basis of the long-term soil erosion test,this paper studied the distribution of C and N in particle size fractions by the method of soil fractions as well as the relationship with sediment amount on dry land in order to study the declining of soil fertility and supervise local fertilization in southern Plateau Loess.The results showed that the contents of organic carbon and nitrogen in clay were highest,medium in silt,and lowest in sand.The organic carbon and nitrogen mainly distributed in silt and clay were lower than 50 μm,and respectively accounted for 97.07% and 85.25% of the soil total amount.The contents of organic carbon and nitrogen in particle size fractions decreased as sediment amount increased.The ratios of C/N in clay gradually increased,and gradually decreased in sand along with the increasing of the sediment amount.The sediment amount with content of organic C and N in clay,silt and sand of soil had an obvious or severe obvious linear relationship.Therefore,the plentiful loss of soil fine particle size fractions was an essential cause to reduce the fertility level on the Loess Plateau. |
| Key words: Loess Plateau soil erosion soil of dry land particle fractions distributions of organic carbon and nitrogen |
